Excerpts from Jim Conrad's
Naturalist Newsletter

from the September 6, 2009 Newsletter, issued from the Siskiyou Mountains west of Grants Pass, Oregon:

Some catkins on the White Alder shown above were infected with fleshy, green and red Alder Tongue Galls caused by the fungus TAPHRINA AMENTORUM. They're shown below:


Most galls I know are produced by insects. The female inserts an egg someplace, cells around the egg then begin multiplying, producing remarkable, typically fleshy structures -- the galls -- and then when the insect larva emerges from the egg it has a lot of fleshy vegetable material to eat. But Alder Tongue Galls result when immature catkin scales are infected with the fungus, which later produces spore-producing fruiting bodies on both gall surfaces.

Of the seven phyla of fungi, Taphrina amentorum belongs to the Ascomycota, so it's related to the mildews, molds and morel mushrooms. In the old days they were referred to as Sac Fungi